Why use the stopbar if you are using a conditional for full length departure sequences? If I've got a queue of departures to blast off in quick succession I just leave the stopbar off and operate as in daylight - one of the few things we are allowed to do at night as per Mats Pt1. If the number two to depart wants to run off the fumes of number one, so much the better for expedition!
However if intersection departures or landing traffic is involved then I just don't use conditionals - I've seen too many ATCOs disciplined when things go wrong - and the time saved is negligable to nothing.
On the subject of stopbars I have noticed that many ATCOs don't bother to extinguish them for vehicles. This is bad practice and is just asking for trouble.
Finally, in the interests of safety may I urge any pilots or airfield vehicle drivers reading this to query any instruction which involves crossing a red stopbar.